Re: Images

[Tass Mailing List <tass@mail.alembic.net>]

Date: Tue, 2 Jan 2007 15:35:44 -0800 (PST)
From: Ron Wickersham <rjw@alembic.com>
To: Tass Mailing List <tass@mail.alembic.net>
Subject: Re: Images

hi Tom,

i'm interested in writing the program to read the disks, pick out the
details that you have identified and any others the wisdom of the list
comes up with.    would work in perl and make a separate application to
search the whole collection.

-ron

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On Tue, 2 Jan 2007, Tass Mailing List wrote:

> Date: Tue, 2 Jan 2007 15:23:36 -0800 (PST)
> From: Tass Mailing List <tass@mail.alembic.net>
> To: Undisclosed recipients:  ;
> Subject: Images
>
>
>
> Date: Tue, 02 Jan 2007 16:50:46 -0600
> From: Thomas F. Droege <droege@fastmail.fm>
> To: tass@tass-survey.org
> Subject: Images
>
> Looking around, I estimate that I have images on 2000 CDs and 200 DVDs.
> Best guess is about 500,000 images.  I would like to get them in a form
> where images containing a particular star could be found.  This is
> important if one tries to use the measurements, since funny things can
> happen to a particular image.  An example is a faint satellite trail
> that crosses a star image.  If faint enough, the data reduction does
> not reject the measurement.  Both V and I images then look somewhat
> brighter, simulating some sort of outburst.  To check this one really
> needs to look at images.  There is probably too much data to be put up
> on a data base.
>
> I propose to start cataloging the image disks.  This is a good mindless
> project for a sick person.  Just set up a system and start feeding all
> the disks through it.  I would propose a small program that would do the
> following:
>
> 1) Read all the fits headers on the disk.
> 2) For each write a summary line.
> 3) Output a file with the name tass_images_n where n is a sequential
> number for each disk. The file would contain a summary line for each
> image pair.  Note that we only have image pairs and we always have image
> pairs.
> 4) I would then go through all the CDs/DVDs and generate the summary
> files.
> 5) I would then label each CD/DVD with it's sequential disk number and
> store them away in 50 disk cake boxes.
>
> It would then be relatively easy to query the summary line file for say
> all the images containing a particular star.  This is not perfect since
> we only have the approximate center of each image stored in the fits
> header.  One could then extract disks 10,457, 2068 relatively easily
> from the stack of cake boxes.
>
> I am willing to read all the disks and set up the cake box stack.  I am
> also willing to answer a reasonable number of queries by manual
> extraction of the images.  If this gets to be a burden, then we have a
> good thing - the data is interesting - and one could go to the trouble
> of loading all the images in some data base.
>
> At the moment, we can't even find a single image set spanning the
> northern sky.  This might be useful and could be easily constructed once
> we had the summary line file.
>
> First we need to agree on what should go in the summary lines.  Some
> things:
> 1)Disk Number
> 2)Image Name
> 3)ra of image center
> 4)dec of image center
> 5)JD t1ime of exposure
> 6)exposure length (we have 100 and 200 second exposures)
> What else?
>
> Then I would need a program to do this.  Any volunteers?  Does not seem
> like a big task for some of you.
>
> Tom Droege
>
> --
>   Thomas F. Droege
>   droege@fastmail.fm
>
>